Camphorataimide B, a maleimide in mycelium of Antrodia camphorate, inhibits progression of human MDA-MB-231 breast cancer cells

Breast cancer is one of the most common malignancies among women worldwide. The degree of metastasis negatively affects a breast cancer patient’s prognosis and treatment benefits. In a previous investigation, camphorataimide B (Cam B), a maleimide derivative, was isolated from the mycelium of Antrodia camphorate, and inhibited cell cycle progression and tumor growth in MDA-MB-231 human breast cancer cells. However, it is not clear whether this compound exerts other anticancer effects. The results demonstrated that synthetic Cam B can inhibit the anchorage-independent growth of MDA-MB-231 breast cancer cells. In addition, Cam B decreased motility and invasion of MDA-MB-231 breast cancer cells. Moreover, Cam B reduced the expression of hypoxiainducible factor-1α (HIF-1α) and its target gene product such as vimentin, cathepsin D and matrix metalloproteinase-2 (MMP-2), which play important roles in tumor progression. Additionally, Cam B reduced the phosphorylation of AKT and p65 NFκB, which associated the downregulation of HIF-1α. Furthermore, Cam B inhibited pulmonary colonization of MDA-MB-231 breast cancer cells in nude mice. By histological and gross examination of mouse lung, it showed that pretreated Cam B reduced the lung colonization of MDA-MB-231 breast cancer cells. The immunohistochemical data exhibited that pretreated Cam B decreased HIF-1α in lung section. These results demonstrate that Cam B reveals a novel role in inhibiting tumor progression.